COMPUTER-SIMULATIONS ON FILLED ELASTOMERIC MATERIALS

Monte Carlo computer simulations have been carried out on filled netwo rks of (amorphous) polyethylene and poly(dimethylsiloxane) using a met hod based on the authors' general theoretical approach for filled elas tomeric materials [Kloczkowski et al., Comput. Polym. Sci. 3 (1993) 39 -45]. This approach enables estimation of the effect of the excluded v olume of filler particles and non-Gaussian characteristics of the chai ns on the elastic properties of the filled networks. It is assumed (i) that the filled polymer network consists of a cross-linked mixture of two types of chains, specifically those attached at one end to spheri cal filler particles and those that are unattached, and (ii) that the elastic modulus of the filled polymer is the sum of contributions from these two types of chains. Distribution functions for the end-to-end vectors of both types of chains were obtained using the Monte Carlo ro tational isomeric state technique proposed by Mark and Curro. In the p resent application, however, conformations of attached chains which ov erlapped with a spherical particle during the simulation were rejected . The elastic moduli of both types of chains were calculated as a func tion of the length of the chains, the size of the filler particles, an d the temperature.